Printing devices that deflect drops using a gas flow are known. U.S. Pat. No. 4,068,241 to Yamada, issued Jan. 10, 1978, entitled “Ink-jet recording device with alternate small and large drops,” describes a printing device that uses a gas flow perpendicular to the drop trajectory to separate large drops and small drops formed by a printhead. The small drops are deflected more by the gas flow than the large drops. The large drops are collected by a catcher while the small drops were deflected past the catcher and allowed to strike a recording medium.
However, it has been determined that while the gas flow does deflect the large and small drops by different amounts, the gas flow past a stream of drops produces drop-drop interactions that affect drop deflection. For example, drop deflection can be affected by the size of and spacing from the previous drop in the drop stream. As a result, the placement of drops on the recording medium can be adversely affected. Additionally, the relative deflection between large drops and small drops can be affected by the preceding drops reducing the ability to catch drops of one size while allowing drops of another size to travel to strike the recording medium.
As such, there is a need for an improved gas flow drop deflection device and a printing apparatus including the same.